NORTHAMPTON – Health officials are advising residents to take precautions after finding the West Nile virus in a mosquito captured in Northampton.

According to an advisory issued by the city’s Board of Health, the state Department of Public Health discovered the virus in a single mosquito sample taken this year. Last year, 3,558 mosquito samples were taken state-wide, 121 of which tested positive.

West Nile virus is transmitted to humans by the bite of mosquitoes infected with it. People over 50 are at particular risk of infection.

Health officials are advising people to take common-sense precautions such as avoiding mosquito bites by rescheduling activities that occur during the evening or early morning, when mosquitoes are most active. They also caution people to use repellent and wear protective clothing. In addition, people can mosquito-proof their homes by removing standing water in the vicinity where mosquitoes tend to lay their eggs.

Because of the recent storm, there is likely more standing water in and around homes than normal. In addition, installing or repairing screens on doors and windows can keep mosquitoes out of the house.

For information and reports about West Nile virus in Massachusetts, go to the Department of Public Health Web site: www.mass.gov/dph/wnv. Recorded information is also available by calling 1-866-627-7968.